1. Field of the Invention
The present invention relates to a method and apparatus for use in locating the eyes of a vehicle driver or passenger for controlling vehicle systems including the positioning of vehicle sideview mirrors in relation to the driver""s eyes to maximize the view of traffic on either side of the vehicle and the characteristics of vehicle airbag deployment.
2. Description of the Background Art
Passenger and commercial vehicles, e.g. automobiles and light trucks, are typically provided with a number of comfort features for the benefit of occupants and safety features and systems that are intended to help avoid collisions or to ameliorate the effects of collisions. At this time, virtually all enclosed vehicles, i.e. automobiles, sport utility vehicles, vans, trucks, etc., are provided with safety belts for use by occupants to strap themselves in. In addition, at least front seat driver""s side and passenger""s side explosively inflated airbags have become standard equipment in such vehicles. Typically, airbags are mounted in the steering wheel hub and in the dash area forward of the front seat passenger and, in some cases, in the vehicle side doors. The airbags are inflated when sudden deceleration of the vehicle is sensed. A force and duration of deployment is currently prescribed that is standardized to average driver and passenger size and seat adjustment position.
Moreover, vehicle mirror assemblies and adjustment systems are provided as standard safety systems in such vehicles. An interior rearview mirror for viewing rearward of the vehicle and exterior left (driver""s side) and right (passenger""s side) sideview mirrors with which the vehicle driver can view traffic to the sides and rear of the vehicle within certain fields of view dictated by the positioning of the mirrors are provided as standard equipment. Typically, the interior rearview mirror can be manually adjusted about horizontal (pitch) and vertical (azimuth) axes through its mount to the headliner or windshield to provide corresponding pitch and azimuth angle adjustment of the view through the vehicle rear window. Even when properly adjusted, the bordering structure of the rear window limits the view to either side. Consequently, vehicles are provided with left and right exterior rearview or sideview mirrors that are typically mounted at the junctures of the left and right windshield pillars with the adjacent front seat side windows. Mechanical or electro-mechanical, remote joystick controls are provided to allow the driver to adjust the sideview mirrors for azimuth (side to side about a vertical axis) and pitch (up and down about a horizontal axis perpendicular to the longitudinal axis of the vehicle). Improper adjustment of the sideview mirrors, particularly in azimuth angle results in wide xe2x80x9cblind zonesxe2x80x9d or xe2x80x9cblind spotsxe2x80x9d on either side of the vehicle.
Such blind zones or spots are widely described in the prior art, and examples are depicted as shown, for example, in the FIGS. 1 and 4 of U.S. Pat. No. 5,033,835. The blind zones on either side generally subtend an azimuth arc angle between the limits of the driver""s peripheral vision while looking ahead and the left and right limits of the fields of view of the left and right sideview mirrors when the mirrors are aimed along the vehicle sides and a pitch angle generally bisected by the horizon. The blind zones are really cone-shaped tunnel areas expanding outward from the sides of the vehicle slightly downward from the eye level of the driver and away from the vehicle sides. Customarily, these right and left blind zones are referred to as blind spots, and that term will be used hereafter.
The current method of exterior sideview mirror alignment used on virtually all domestic and imported passenger vehicles simply relies on the driver""s judgment as to the proper imagery he/she should see reflected by the sideview mirror. This is supposedly gained by experience with different settings. Many drivers erroneously believe that correct azimuth angle alignment is achieved when the side panels of their own vehicle are reflected back to them along one edge of the exterior sideview mirrors when they are in their normal driving position.
A wide number of solutions to the problem of correctly setting the sideview mirror position to maximize the view of the blind spot have been proposed but not adopted. One approach is to attempt to enlarge the viewing angle. Wide viewing angle, static mounted, sideview mirrors and dynamically movable sideview mirrors are the subjects of U.S. Pat. Nos. 4,019,812, 4,187,001, 4,318,590, 4,439,813, 4,575,202, 4,792,220 and 4,971,930. All of these proposed solutions require either bulky assemblies, distort the image in the field of view so that the driver does not see all the potential safety hazards in correct prospective, or are complex electro-mechanical systems with intermittent or continuously running motors and subsequent noise and vehicle power drain.
Further approaches to solving the problem of correctly aligning the sideview mirrors to eliminate or minimize blind spots are set forth in U.S., Pat. Nos. 5,022,747, 5,033,835, 5,122,910 and 5,237,458. The ""747, ""835 and ""910 patents employ an auxiliary mirror built into a corner of the sideview mirror which images a reference point or marker on the vehicle side to which the mirror is mounted when the main mirror is properly aligned to image the vehicle blind spot. In another form of the ""835 patent, the sideview mirror is first adjusted by the driver to image the reference point, and then the electro-mechanical system changes the alignment a preset amount to image the blind spot. A lamp on the adjustment mechanism lights when the final alignment position is achieved by the system.
The use of auxiliary mirrors on or visible through the front surface of the main sideview mirror that are large enough to view a vehicle reference point reduces the mirror surface area for viewing into the blind spot. Also, the imaged target on the side of the vehicle may not always be clearly visible due to road grime on the vehicle or simply because of low ambient lighting. Finally, salient auxiliary mirrors and targets on the side of the vehicle large enough to be seen by the driver are anathema to automotive stylists.
Moreover, such approaches provide only a limited range of correct mirror adjustment and are not usable in all seat positions for all driver heights. In this regard, it should be noted that the ""747 and ""910 patents profess that their disclosed systems are insensitive to driver height and seat position of up to 8 inches fore and aft and up and down from a xe2x80x9cstandard driverxe2x80x9d. However, the illustrations of FIGS. 8 and 9 confirm that the rearward views attained at these nonstandard positions do widely vary and are not ideal. The ability of the non-standard driver to rely on the setting attained by imaging the vehicle targets depends greatly on how large the sideview mirror surface is. As vehicle manufacturers seek to minimize sideview mirror size for styling and economy reasons, it is clear that this approach may well mislead drivers of non-standard height or seat position preference.
The ""458 patent professes to be an improvement on the earlier system of the ""747 and ""910 patents and discloses a light source 9 in the mirror housing 3 that illuminates a target 7 or is an illuminated target. The target 7 is reflected by an auxiliary mirror 6 and through a light transmissive portion 5 of the sideview mirror 4. It would appear that the targeting approach taken in this system is geared toward ensuring that an exact correct alignment is attained for a xe2x80x9cstandard driverxe2x80x9d, and all other driver positions are only approximately correct. Again, the adequacy of the sideview mirror setting for non-standard driver eye locations is highly dependent on the amount of the sideview mirror surface area.
In a further approach, certain automobiles have auxiliary turn signal indicators mounted above the front wheel wells to alert the oncoming driver in the blind spot to the intention of the blinded driver to make a turn or lane change into that lane. It is also proposed to mount the auxiliary turn signal lights to the sideview mirror structure as disclosed, for example, in U.S. Pat. Nos. 4,906,085, 5,014,167 and 5,207,492 Unfortunately these forward mounted, auxiliary turn signal lights may alert an overtaking driver in the adjacent lane too late to be totally effective, and may even encourage drivers to fail to properly set their sideview mirror azimuth angles or to even use their sideview mirrors before initiating a lane change. In the latter case, careless drivers frequently change lanes without using their turn signals or sideview mirrors. Finally, due to their fields of view, if sideview mirrors having such auxiliary turn signals are not properly adjusted in the first place, the auxiliary turn signals may not be seen by an overtaking vehicle in time to react.
Turning to a further aspect of sideview mirror adjustment, frequently, two or more individuals may drive the same vehicle and each adjust the rearview and sideview mirrors to their own liking. To avoid the inconvenience of each driver in having to readjust the rearview and sideview mirrors, it has been proposed that mirror settings be memorized for re-use when a specific driver identification code is entered. The adjustments that are typically made by different drivers are mirror pitch about the horizontal axis depending on the driver""s height or both the mirror pitch and azimuth, if the driver changes the seat height or distance from the steering wheel. In certain vehicles having memorized driver seat positions, the mirror pitch and azimuth adjustment angles are memorized with the seat positions as shown, for example, in U.S. Pat. Nos. 4,267,494, 4,625,329 and 4,727,302. Such systems do not necessarily provide the optimum mirror adjustments for eliminating blind spots, but instead rely on the drivers to make the initial settings that are then memorized.
Many vehicle accidents could be prevented with a simple opto-electronic mirror adjustment aid for left and right sideview mirror alignments to embrace the blind spots peculiar to each vehicle model in the reflected images seen by the driver. To be adapted by vehicle manufacturers, such an aid must be inexpensive, reliable, consume minimal power, and be able to be incorporated with new or existing mirror housings subject to whatever styling considerations are imposed. To be accepted by the driving public, the aid must be simple to operate and must inherently compensate, at least approximately, for variations in driver height and seat position. This inherent compensation should be automatic and occur as the vehicle operator uses the aid""s optical cues during mirror alignment. Moreover, when used, the aid should provide positive feedback to the driver that assures him/her that the alignment is correct, even if it appears to the driver to be incorrect. These goals are all met with the embodiments of the present invention described in detail hereafter.
Returning to the use of explosively inflatable airbags, the deployment of the airbags is beneficial or not harmful in the majority of cases. However, injuries to or death of small stature adults, children and infants have been attributed to the airbag deployment force. The force and duration of deployment is standardized to protect an average sized adult located at an average distance from the airbag. If the person is smaller in size and closer than the average distance, the force and duration can be excessive and cause injury or death. In the case of injuries to or deaths of infants, many are caused by failure to use or to properly attach an infant seat to the front passenger""s seat belts. Moreover, while the airbag force and duration is standardized to a particular distance, the combination of the seat adjustment and the form or shape of the infant""s seat may place the infant in jeopardy. This has led to efforts to educate the driving public to locate infants and children in rear seats which many parents find unacceptable or inconvenient. Despite the clear evidence that airbags and seat belts combine to save many lives, some are urging that they be allowed to optionally disable the airbag deployment system. Rather than such an extreme solution, it would be more desirable to modulate the force and duration of the deployment to take into account the size and location of the driver and front seat passenger or infant""s seat.
Many of the considerations to be taken into account and a system block diagram for making the deployment decision and controlling the deployment force and duration or rate of deployment of single stage or multi-stage airbags are set forth in the article entitled xe2x80x9cRestraint system electronicsxe2x80x9d, Automotive Engineering August, 1996, pp. 27-31, incorporated herein by reference. In this article, a variety of sensors are described for attempting to determine the position of the driver, passenger(s) and infant seat and other vehicle characteristics, e.g. vehicle speed and the like, that provide signals that are proposed to be combined to control the deployment of airbag(s). Unfortunately, many of these sensors, e.g., seat position sensors, seat belt attachment sensors, weight on the seat measuring sensors are ambivalent or imprecise and can be fooled. Difficulties encountered with attempted use of a variety of sensors to locate a person in a front driver""s or passenger""s seat are set forth in the article xe2x80x9cWhat""s a smart airbag""s real IQxe2x80x9d, Automotive News, Feb. 24, 1997, p.1.
One further methodology for determining the location of a vehicle occupant employing optical rangefinding techniques is described in the article by W. Chapelle entitled
xe2x80x9cSensing Automobile Occupant Position with Optical Triangulationxe2x80x9d, SENSORS, December 1995, p. 18+, incorporated herein by reference. This system requires use of a light projector, imaging lenses and photosensor arrays that are similar to those used in photographic cameras with a projection light source. In such systems, it is difficult for the system to determine just what aspect of the driver, passenger of other object is being imaged. Again, such systems can be fooled by imaging on the wrong feature.
The above-described patents do not determine the location of the eyes of a driver or passenger. Further U.S. Pat. Nos. 4,797,824 and 4,843,892 do seek to determine the eye positon of a driver. The ""824 patent is directed to a system for locating the driver""s eye height in order to control the automatic adjustment of the height of a seat head rest. A horizonatal array of differently colored light sources provide a corresponding vertically stacked array of light beams that are spread horizonatally so that the driver can see one of the fight beam colors with both eyes. The driver indicates which of the light beam colors is most intensely visible, and the coordinates of that light beam are used with the fore-aft seat and seat back angle position information to determine the driver""s eye height or xe2x80x9cYxe2x80x9d component of the X, Y, Z Cartesian coordinates of the driver""s eyes. In this case, it is not necessary and no means are provided to determine the xe2x80x9cXxe2x80x9d and xe2x80x9cZxe2x80x9d components.
The ""892 patent discloses an eye position detection system for adjustment of vehicle mirrors that relies upon the driver aligning a sight marking on the interior rearview mirror with a sight marking on the vehicle rear window and pickoffs for detecting the pitch and azimuth adjustment angles of the rearview mirror. When the driver indicates that the alignment is achieved, the driver""s eye position is determined using the fore-aft seat plane and rearview mirror Cartesian coordinates, assuming the the driver is centered in the fore-aft seat plane. This approach cannot be used in dim light or at night.
Moreover, most people tend to favor one eye over the other eye when sighting or aligning images and objects. This can lead to an error in azimuth determination of the hypothetical xe2x80x9cXxe2x80x9d coordinate component, which is ideally the center-point between the right and left eyes.
A more accurate and less ambivalent system for determining the X, Y, Z Cartesian coordinates of the centerpoint of the eyes of a driver or passenger in a vehicle seat is needed for the adjustment of the vehicle sideview mirrors and other vehicle components and systems.
The present invention provides a method and apparatus for locating a driver""s eyes or a passenger""s eyes to allow for the automatic adjustment of vehicle systems to their eye locations.
The methods and systems or the present invention derive the location of a driver""s or passenger""s eyes from the adjustment by the driver (or passenger, if capable of doing so) of a light beam pair comprising right eye and left eye light beams. The directions of the right and left light beams are adjustable in tandem by the driver, the adjustments in pitch and azimuth about pitch and azimuth light beam adjustment axes having known Cartesian coordinates. The driver or passenger adjusts the left eye beam and a right eye beam in tandem until they impinge upon the respective left eye and right eye with perceived maximal equal intensity. The right and left eye beams may be of the same or differing colors.
In certain embodiments, the right eye beam and left eye beam are emitted from a common light beam housing, particularly from respective right and left light beam emitting locations that are offset in the horizontal, azimuth, direction (or X coordinate) from one another and from the common adjustment axes of the light beam pair. The right and left eye light beams are nominally directed in the same direction but diverge apart slightly in the azimuth direction. The angular adjustment of the light beam housing is detected, and the location of the driver""s or passenger""s eyes is computationally derived as a set of Cartesian coordinates from the tandem adjustment of the binocular light beams and other known Cartesian coordinates of the vehicle.
Assuming a single light source housing for the moment, the pitch and azimuth adjustment angles of the housing are measured when the driver or passenger indicates that he or she perceives the right and left eye light beams to be equal and maximal in intensity. Pitch and azimuth angle adjustment measurement means, e.g., miniature angle resolvers or xe2x80x9cpickoffsxe2x80x9d are associated with the housing to measure the pitch and/or azimuth angles of adjustment of the light beams. The location of the driver""s or passenger""s eyes is determined using triangulation techniques employing the measured angles and the known Cartesian coordinates of pitch and azimuth axes of adjustment of the adjustable light beam housing and the known fore-aft seat adjustment plane for the respective driver""s or passenger""s front seat. This approach assumes that the driver or passenger is centered in the driver""s or front passenger""s seat and therefor is centered in the fore-aft seat plane.
To provide a somewhat more accurate location of the respective eyes, at least two light housings are employed, each emitting right and left eye light beams. The direction of the light beams is adjusted using either a pitch and azimuth adjustable light mount or an adjustable light beam reflector intersecting a fixed direction light beam from a fixed light source. The angles of adjustment in pitch and azimuth of both light beams are measured when both light beam pairs are adjusted to be seen by the eyes. The location of the driver""s or passenger""s eyes is determined from both sets of measured pitch and azimuth angles and the known Cartesian coordinates of the light beam pitch and azimuth axes, employing triangulation techniques.
The present invention may be embodied in other embodiments where the light beam pair housing is not itself adjustable, and the right and left eye light beams are reflected from an auxiliary mirror or reflector associated with the interior rearview mirror or one or both of the sideview mirrors. The combined mirror and reflector is adjustable in pitch and/or azimuth about respective pitch and/or azimuth adjustment axes by the driver until the light beams are visible to the driver""s or passenger""s eyes. Pitch and azimuth angle adjustment measurement pickoffs are associated with the mirror to measure the pitch and/or azimuth angles of adjustment of the reflector. The eye location intermediate the right and left eye is derived from the measured angles of adjustment. Then, the sideview mirror pitch and azimuth adjustment signal sets and/or airbag deployment control signals are derived and employed as summarized above.
The determined driver""s eye location can be used together with the known pitch and azimuth axes of adjustment of the driver""s and passenger""s sideview mirror assemblies and known Cartesian coordinates of the vehicle blind spots to derive exterior sideview mirror pitch and azimuth adjustment signal sets. The adjustment signals are applied to feedback servo motors operating in a feedback control loop to correct the driver""s side and passenger""s side sideview mirror pitch and azimuth settings to properly reflect images of the driver""s side and passenger""s side vehicle blind spots to the driver""s eyes.
The determined eye locations of the driver and passenger may be also or alternatively employed in the control of the airbag deployment system. The relative fore-aft distance away from the airbag and the height of the person can be computed, and airbag deployment force and/or duration adjusted to compensate for deviation from the standard height and fore-aft distance.
The determination of the location of the driver""s and passenger""s eyes also allows a number of vehicle safety and comfort systems to be advantageously optimized, including climate control, seat level, radio settings, other mirrors, etc.
The eye location aids of the present invention may advantageously be employed with both vehicle sideview mirrors and coordinated with the setting of the interior rearview mirror in a variety of combinations and permutations. The additional components of the mirror assembly (if any, in the particular combination) are relatively inexpensive and durable. In the disclosed embodiments and variations where the light source(s) are located within the vehicle in association with the vehicle rearview mirror or otherwise positioned therein, the existing vehicle sideview mirror assemblies need not be modified, other than adding mirror pitch and azimuth angle pickoffs to control sideview mirror positioning under feedback control by the microcomputer. The eye location, sideview mirror alignment and air bag deployment adjustment may be implemented employing the existing vehicle microcomputer or a separate inexpensive on-board microcomputer.
The interior locations of the light sources avoids any problems of passing the light beam pair through the vehicle door windows in bad weather or due to grime.
Through use of the alignment aids of the present invention, accuracy in positioning of the sideview mirrors to reflect objects in the vehicle blind spot and driver appreciation of the proper mirror settings are greatly increased, hopefully resulting in lower frequency of accidents and injury. In each case where sideview mirror positioning signals are derived outside of direct control by the driver, the driver may be provided with the ability to manually override the sideview mirror pitch and azimuth settings for safety reasons.
The risk of injury due to airbag deployment force may be diminished through correlation of the airbag deployment force and duration to the size and location of a driver or passenger in the driver""s or passenger""s seat as determined in accordance with the teachings of the present invention.
This summary of the invention and the objects, advantages and features thereof have been presented here simply to point out some of the ways that the invention overcomes difficulties presented in the prior art and to distinguish the invention from the prior art and is not intended to operate in any manner as a limitation on the interpretation of claims that are presented initially in the patent application and that are ultimately granted.